Phase change memory devices and methods comprising gallium, lanthanide and chalcogenide compounds
AssigneeUniversity of South Hampton
InventorsDaniel William Hewak, Richard J. Curry, Arshad Khawar Mairaj, Robert E. Simpson
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Abstract
A new class of phase change materials has been discovered based on compounds of: Ga; lanthanide; and chalcogenide. This includes compounds of Ga, La, and S (GLS) as well as related compounds in which there is substitution of S with O, Se and/or Te. Moreover, La can be substituted with other lanthanide series elements. It has been demonstrated that this class of materials exhibit low energy switching. For example, the GLS material can provide an optical recording medium with erasability 3-5 dB greater than the erasability of GeSbTe (GST) material which is the standard material for phase change memories.
Claims34
A phase change memory device comprising a phase change material, wherein the phase change material is a compound of:
- (Ga)w(La)x(chalcogenide)y
- wherein:
- La is La or La and at least one further lanthanide element;
- the chalcogenide is composed of Te;
- and
- the ratio of atoms is in the range of 25<w<35, 5<x<15, 50<y<70.
A phase change memory device comprising a phase change material, wherein the phase change material is a compound of:
- (Ga)w(La)x(chalcogenide)y
- wherein:
- La is La or La and at least one further lanthanide element;
- the chalcogenide is composed of S and at least one other element selected from O, Se, and Te,
- the ratio of atoms is in the range of 25<w<35, 5<x<15, 50<y<70.
A method of operating a phase change memory device by selectively switching a compound between a first state and a second state, the compound of:
- (Ga)w(La)x(chacogenide)y
- wherein:
- La is La or La and at least one further lanthanide element;
- chalcogenide comprises at least one of S and Te;
- and
- the ratio of atoms is in the range of 25<w<35, 5<x<15, 50<y<70;
- and
- wherein the first state and the second state are first and second crystalline phases of the phase change material.
Dependencies are inferred from the claim text.